VIDEO: How to Use a Refractometer

The refractometer is the Apple Watch of the coffee world. It’s a small gadget with immense capabilities – ones, admittedly, that some might consider unnecessary – and a collection of passionate fans.

But what actually is it and how to do you use it? Find out in today’s video article.

What Does a Refractometer Measure?

A refractometer measures something called total dissolved solids (TDS), which is pretty much exactly what it sounds like. Brewers can use this to calculate the extraction yield. Simply take the weight in grams of the brewed coffee, multiply it by the TDS, and then divide the result by the weight in grams of the coffee grams. A good yield is typically considered to be 18-22%, although some prefer it to be above 21%.

How to Use a Refractometer

Matt Perger (WBrC Champion 2012, WCiGS Champion 2014, and two-time WBC finalist) demonstrates how to use a VST Lab Refractometer in this video. His step-by-step instructions will make using these tools a breeze.

However, coffee champion Chris Baca also reminds us that extraction yields should be a guideline, not a hard and fast rule. Since taste is the priority, he recommends using it only to ensure consistency. Here’s why: